框架本地无法运行，修复尝试

vendor/phpoffice/math/src/Math/Reader/MathML.php

@@ -10,7 +10,6 @@ use PhpOffice\Math\Element;
 use PhpOffice\Math\Exception\InvalidInputException;
 use PhpOffice\Math\Exception\NotImplementedException;
 use PhpOffice\Math\Math;
-use PhpOffice\Math\Reader\Security\XmlScanner;
 
 class MathML implements ReaderInterface
 {
@@ -23,17 +22,8 @@ class MathML implements ReaderInterface
     /** @var DOMXPath */
     private $xpath;
 
-    /** @var XmlScanner */
-    private $xmlScanner;
-
-    public function __construct()
-    {
-        $this->xmlScanner = XmlScanner::getInstance();
-    }
-
     public function read(string $content): ?Math
     {
-        $content = $this->xmlScanner->scan($content);
         $content = str_replace(
             [
                 '⁢',
@@ -45,7 +35,7 @@ class MathML implements ReaderInterface
         );
 
         $this->dom = new DOMDocument();
-        $this->dom->loadXML($content);
+        $this->dom->loadXML($content, LIBXML_DTDLOAD);
 
         $this->math = new Math();
         $this->parseNode(null, $this->math);

vendor/phpoffice/math/src/Math/Writer/MathML.php

@@ -40,26 +40,6 @@ class MathML implements WriterInterface
     {
         $tagName = $this->getElementTagName($element);
 
-        // Element\AbstractGroupElement
-        if ($element instanceof Element\Semantics) {
-            $this->output->startElement($tagName);
-            // Write elements
-            foreach ($element->getElements() as $childElement) {
-                $this->writeElementItem($childElement);
-            }
-
-            // Write annotations
-            foreach ($element->getAnnotations() as $encoding => $annotation) {
-                $this->output->startElement('annotation');
-                $this->output->writeAttribute('encoding', $encoding);
-                $this->output->text($annotation);
-                $this->output->endElement();
-            }
-            $this->output->endElement();
-
-            return;
-        }
-
         // Element\AbstractGroupElement
         if ($element instanceof Element\AbstractGroupElement) {
             $this->output->startElement($tagName);
@@ -141,9 +121,6 @@ class MathML implements WriterInterface
         if ($element instanceof Element\Operator) {
             return 'mo';
         }
-        if ($element instanceof Element\Semantics) {
-            return 'semantics';
-        }
 
         throw new NotImplementedException(sprintf(
             '%s : The element of the class `%s` has no tag name',